|
By selecting an appropriate cross-host, we minimized a number of problems, including compatible byte sex, structure data alignment, program size, and existing tool set. Floating point data format turned out to be a minor concern because few programs in the early utilities group require it. Thanks to the IEEE floating point standard, this becomes easy as most post-VAX period processors support the same format (modulo byte order). Obviously, our job would have been simpler if we already had 386BSD up and running and then had to port it, so what we looked for in a cross-host was something very similar. Oddly enough, a C compiler hides most of the native machine's instruction set, so the least important part is the cross-host's processor architecture. Operating system version and program development tool similarity count for much more. Those more dogmatic, gutsy, or energetic might say that we simply avoided the hard parts. They are quite correct. What hardships we did endure in cross-tools were more than enough for us.
|
|